For many beverages, it is necessary to carry out the filling operation under aseptic conditions. It is known that a sterilisation process for aseptic filling starts with the sterilisation of the already manufactured bottles in a clean chamber provided for this purpose. All the processes that take place beforehand in the prior art, such as the production of the preforms, the transport thereof, the heating thereof and the blow molding thereof to form the bottle, take place in a non-sterile environment. In this case, it is necessary to sterilise a relatively large surface area, namely the surface area of the plastic bottle that has already been produced.
Containers which are to be filled with sensitive filling product may be sterilised for example by heating the filling product and filling it in the hot state into the container and sterilising the inside of the bottle with the hot filling product. Furthermore, it is also possible that the empty container is sterilised separately prior to the filling process and is filled under aseptic conditions with the filling product that has been sterilised elsewhere. The sterility of the empty container is in this case achieved by using chemical disinfectants such as peracetic acid (wet) or hydrogen peroxide (dry). To this end, the containers are conveyed into a so-called isolator, in which disinfectant is applied thereto and must be left to act for a certain period of time and then must be removed again with great effort. With this procedure, there is a problem concerning residues. The aseptically encapsulated filling machine is arranged directly after this isolator. However, this technology is still relatively complicated.
It is therefore usually desirable to sterilise not the plastic bottle itself but rather the plastic preform, since this has a much smaller surface area. However, it is necessary to transport the containers after the sterilisation thereof, in particularly constantly, under sterile conditions, at least until they are closed, in order in this way to prevent further contamination of the containers.
EP 0 794 903 B1 describes a system and a method for the sterile packaging of beverages. In said document, a beverage container is formed from a shaped preform by blow molding, then the container is filled with a sterile beverage and finally the filled container is filled with a sterilised closure cap. In this case, different degrees of sterilisation are controlled in different parts of the chamber, wherein the degrees of sterilisation are correlated with the degree required for the method step carried out in the relevant part of the chamber.
In this production method, the entire bottle production process and also the filling and closing process is carried out constantly under sterile conditions. A complete shaping unit for the containers is also arranged in a clean chamber. This method ensures a high degree of sterilisation and cleanliness of the containers filled in this way. On the other hand, however, the complexity of the sterilisation is relatively high since on the one hand very large areas have to be kept sterile and on the other hand there is a large number of machine parts, specifically in the region of the blow molding device, which must be kept sterile.
The object of the present invention is therefore to reduce the complexity of sterilising and keeping sterile a shaping unit or blow molding device for containers. On the other hand, however, production conditions which are as sterile as possible should be provided for the containers.
An apparatus described in WO 2010 020 529 A2 for shaping plastic preforms into plastic containers comprises a transport device on which a plurality of blow molding stations are arranged, wherein each of these blow molding stations comprises a blow mold inside which a plastic preform can be shaped into a plastic container, and wherein the apparatus comprises a clean chamber inside which the containers can be transported. Furthermore, that region of the transport device in which the blow molding stations are arranged is arranged in the clean chamber and a further region of the transport device is arranged outside the clean chamber.
In this apparatus, therefore, a clean chamber channel is provided, through which the plastic preforms or containers are conveyed in the blow molding stations, and a further region of the transport device is moved outside the clean chamber. Parts of the shaping unit, such as a blow molding machine, e.g. the entire blow molding wheel or the blow molding cavities, are thus separated from the rest of the blow molding machine by a clean chamber or closed isolator.
The subject matter of WO 2010 020 529 A2 is hereby fully incorporated by way of reference into the subject matter of the present application. However, the applicant has found that, although satisfactory results can already be achieved with the aforementioned apparatus of WO 2010 020 529 A2, a further reduction in the volume of the clean chamber is nevertheless possible.